Quote:
Originally Posted by gtofreek
I showed Joe's video to another machinist who owned his own machine shop for over 25 years. I suggested nothing, just asked him to watch and see what he thinks the noise might be. As soon as it started knosking, the first words out of his mouth is "that's spark knock". I personally have never heard spark knock at an idle so I asked him to clarify. He said the engine is running too slow to deal with the amount of timing it has and it's causing a spark knock. Spark knock is NOT a machanical knock[which would explain why I found nothing in the engine that would cause a mechanical knock]. It's an ignition knock. This has been suggested many times in this thread but seems to fall on deaf ears.
I pulled the distributor when I got the engine back from dyno. I checked the busing which was fine and I restabbed the distributor BUT had no way of setting the timing. That is why I wrote on a piece of tape on the carb plate that the timing needs to be reset. It was only close enough to get the engine to start and run.
You need to get the idle RPM up and not down at 400-500 RPM. That's just ridiculously slow for an engine with this much cam in it. I only hear the knock at this really low idle. Pick the idle up, set the timing as I wrote on the tape, and disconnect the vacuum advance for the distributor and plug the vacuum port on the carb., then see if the noise is still present. I bet it won't be there.
Tighten up that alternator belt also. It's way too loose.
I feel once the timing and idle speed have been dealt with, the knocking noise will be non-existent.
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Do this!!! Just validated the timing is not set on this motor correctly.